title: Pressure tolerance of the shallow-water caridean shrimp Palaemonetes varians across its thermal tolerance window.
abstract: To date, no published study has assessed the full physiological scope of a marine invertebrate species with respect to both temperature and hydrostatic pressure. In this study, adult specimens of the shallow-water shrimp species Palaemonetes varians were subjected to a temperature/pressure regime from 5 to 30°C and from 0.1 to 30 MPa. The rate of oxygen consumption and behaviour in response to varying temperature/pressure combinations were assessed. Rates of oxygen consumption were primarily affected by temperature. Low rates of oxygen consumption were observed at 5 and 10°C across all pressures and were not statistically distinct (P=0.639). From 10 to 30°C, the rate of oxygen consumption increased with temperature; this increase was statistically significant (P<0.001). Palaemonetes varians showed an increasing sensitivity to pressure with decreasing temperature; however, shrimp were capable of tolerating hydrostatic pressures found outside their normal bathymetric distribution at all temperatures. 'Loss of equilibrium' (LOE) in ≥50% of individuals was observed at 11 MPa at 5°C, 15 MPa at 10°C, 20 MPa at 20°C and 21 MPa at 30°C. From 5 to 20°C, mean levels of LOE decreased with temperature; this was significant (P<0.001). Low mean levels of LOE were observed at 20 and 30°C and were not distinct (P=0.985). The physiological capability of P. varians to tolerate a wide range of temperatures and significant hydrostatic pressure is discussed.
authors.affiliation: School of Ocean and Earth Sciences, University of Southampton, National Oceanography Centre Southampton, European Way, Southampton SO14 3ZH, UK. svth@noc.soton.ac.uk
authors.forename: Andrew
authors.initials: A
authors.lastname: Oliphant
authors.forename: Sven
authors.initials: S
authors.lastname: Thatje
authors.forename: Alastair
authors.initials: A
authors.lastname: Brown
authors.forename: Marina
authors.initials: M
authors.lastname: Morini
authors.forename: Juliette
authors.initials: J
authors.lastname: Ravaux
authors.forename: Bruce
authors.initials: B
authors.lastname: Shillito
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D006874:Hydrostatic Pressure; D010101:Oxygen Consumption; D033541:Palaemonidae / Q000502:physiology*; D013696:Temperature